1 /*
   2  * Copyright (c) 1997, 2003, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 class LoopTree;
  26 class LRG;
  27 class LRG_List;
  28 class Matcher;
  29 class PhaseIFG;
  30 class PhaseCFG;
  31 
  32 //------------------------------PhaseCoalesce----------------------------------
  33 class PhaseCoalesce : public Phase {
  34 protected:
  35   PhaseChaitin &_phc;
  36 
  37 public:
  38   // Coalesce copies
  39   PhaseCoalesce( PhaseChaitin &chaitin ) : Phase(Coalesce), _phc(chaitin) { }
  40 
  41   virtual void verify() = 0;
  42 
  43   // Coalesce copies
  44   void coalesce_driver( );
  45 
  46   // Coalesce copies in this block
  47   virtual void coalesce( Block *b ) = 0;
  48 
  49   // Attempt to coalesce live ranges defined by these 2
  50   void combine_these_two( Node *n1, Node *n2 );
  51 
  52   LRG &lrgs( uint lidx ) { return _phc.lrgs(lidx); }
  53 #ifndef PRODUCT
  54   // Dump internally name
  55   void dump( Node *n ) const;
  56   // Dump whole shebang
  57   void dump() const;
  58 #endif
  59 };
  60 
  61 //------------------------------PhaseAggressiveCoalesce------------------------
  62 // Aggressively, pessimistic coalesce copies.  Aggressive means ignore graph
  63 // colorability; perhaps coalescing to the point of forcing a spill.
  64 // Pessimistic means we cannot coalesce if 2 live ranges interfere.  This
  65 // implies we do not hit a fixed point right away.
  66 class PhaseAggressiveCoalesce : public PhaseCoalesce {
  67   uint _unique;
  68 public:
  69   // Coalesce copies
  70   PhaseAggressiveCoalesce( PhaseChaitin &chaitin ) : PhaseCoalesce(chaitin) {}
  71 
  72   virtual void verify() { };
  73 
  74   // Aggressively coalesce copies in this block
  75   virtual void coalesce( Block *b );
  76 
  77   // Where I fail to coalesce, manifest virtual copies as the Real Thing
  78   void insert_copies( Matcher &matcher );
  79 
  80   // Copy insertion needs some smarts in case live ranges overlap
  81   void insert_copy_with_overlap( Block *b, Node *copy, uint dst_name, uint src_name );
  82 };
  83 
  84 
  85 //------------------------------PhaseConservativeCoalesce----------------------
  86 // Conservatively, pessimistic coalesce copies.  Conservative means do not
  87 // coalesce if the resultant live range will be uncolorable.  Pessimistic
  88 // means we cannot coalesce if 2 live ranges interfere.  This implies we do
  89 // not hit a fixed point right away.
  90 class PhaseConservativeCoalesce : public PhaseCoalesce {
  91   IndexSet _ulr;               // Union live range interferences
  92 public:
  93   // Coalesce copies
  94   PhaseConservativeCoalesce( PhaseChaitin &chaitin );
  95 
  96   virtual void verify();
  97 
  98   // Conservatively coalesce copies in this block
  99   virtual void coalesce( Block *b );
 100 
 101   // Coalesce this chain of copies away
 102   bool copy_copy( Node *dst_copy, Node *src_copy, Block *b, uint bindex );
 103 
 104   void union_helper( Node *lr1_node, Node *lr2_node, uint lr1, uint lr2, Node *src_def, Node *dst_copy, Node *src_copy, Block *b, uint bindex );
 105 
 106   uint compute_separating_interferences(Node *dst_copy, Node *src_copy, Block *b, uint bindex, RegMask &rm, uint rm_size, uint reg_degree, uint lr1, uint lr2);
 107 
 108   void update_ifg(uint lr1, uint lr2, IndexSet *n_lr1, IndexSet *n_lr2);
 109 };